i have play with 14 bit~lossess for somedays.i found something interesting.

i opened dng files come form mlv_dump with dcraw then repaired black level in matlab just like

this.

`dcraw = 'dcraw -c -4 -D';`

system(sprintf('%s "%s" > tmp.pgm', dcraw, filename));

a = double(imread('tmp.pgm'));

[m,n]=size(a);

for i=1:2:m

for j=1:2:n

out(i,j)=a(i,j)+128;

out(i,j+1)=a(i,j+1)+256;

out(1+i,j)=a(1+i,j)+512;

out(i+1,j+1)=a(i+1,j+1)+1024;

then i did demosaicking in matlab with the demosaic function and output tiff file.

the output image looks very dark.after add on five levels of exposure it looks well.however, i found this way give me lots of noise.

it's strange since i take the photo with a low iso(400) it shouldn't give so many noise.so i did some more research.

i took two mlvs.one is over exposured(+5e) and the other one is totally dark(-10.5).take dngs from them and repair black-level in matlab.for over exposured,max figure is 16382 and for dark image,the average is 2047 and min is 2038.then,for the 0ev image, average is 2150,max 16124, min 2059.

so..it means almost all -10.5~0ev pixels' data were written within 8bit.(2150-2047)*2=206.

i have no idea if highlight data use the range of 2^14-2^7 ,but it seems impossable.

so...maybe for some reasons 6d record wrong data or mlv_dump can't change 14bit~lossess mlv from 6d to dng currectlly...or...for some other reasons.who knows.

sorry for my poor english.